On order to successfully translate basic research in leukemia to the clinical setting, as well as to better understand the relevance of observed clinical or population-based phenomena through laboratory-based research, an extensive repository of tissue samples, with accompanying pathologic and clinical data, procured from leukemia patients is necessary. To fulfill this role. Core A will provide researchers in the Leukemia SPORE access to a relatively unprecedented repository of uniformly prepared and fully characterized leukemia patient samples. The already well-established Ohio State University and CALGB Leukemia Tissue Banks (referred to as SPORE LTBs) constitute the backbone of Core A, and contribute crucial experience and infrastructure to this effort. The SPORE LTBs serves as centralized tissue banks of blood and bone marrow specimens, as well as non-leukemic material, procured from leukemia patients enrolled on CALGB or OSU treatment protocols, and provide these to investigators within and outside of OSU. This work will integrate with Cores B (biostatistics) and C (Biomedical informatics) to maintain a detailed, current database of samples and accompanying clinical information available. Beyond simply serving as a cell repository. Core A will perform regular validation of sample quality, conduct molecular characterizations, and prepare derivatives (protein, DNA, RNA). The availability of this infrastructure for procuring samples, and the large number of samples already in our possession, will greatly facilitate the conduct of the research projects of this SPORE proposal as well as provide an important and widely available resource for extended studies by investigators within this or outside the OSU Leukemia SPORE. The specific aims of Core A are: (1) To provide central collection, processing and a state-of- the-art repository for samples collected from leukemia patients treated on clinical protocols that are relevant to the OSU Leukemia SPORE; (2) To provide materials from processed clinical samples to interested investigators, within and outside of the OSU Leukemia SPORE, who examine relevant cellular and molecular properties of leukemia and correlate these properties with clinical or population-based outcomes and who commit to sharing the data derived from their research efforts. The effective collection and characterization of leukemia samples by Core A and their provision to SPORE investigators is critical to the success of the research proposed. The infrastructure of this Core A is therefore already in place, and partially supported through NCI funding through both the CALGB and OSUCCC, In this Core proposal, we seek supplemental and not overlapping funding for support ofthe SPORE projects RELEVANCE (See instructions): Biological mechanistic investigations rely on cell lines or animal models. While these are powerful research tools, validating laboratory findings in human tissue is crucial to understand their relevance to human disease. This Core will provide SPORE researchers with simplified access to a large repository of leukemia patient samples and accompanying clinical information. This multi-tiered effort is essential to the overall goal of this SPORE group to bring their findings to the practical benefit of patients with leukemia.